Project Summary/Abstract Metastatic melanoma is challenging to clinically address. Although standard of care combination BRAF and MEK inhibitor (BRAFi/MEKi) therapy has high response rates in patients with BRAF-mutant melanoma, therapy relapse occurs in most cases. Work from our laboratory and others in the field has identified subpopulations of intrinsically BRAFi/MEKi-resistant melanoma cells that are highly metastatic and drivers of therapy relapse. These ?persistent? melanoma cells display molecular and biologic properties akin to neural crest stem cells (NCSC), including high invasiveness, plasticity and self-renewal capacity. Our long-term goal is to elucidate the dominant molecular mechanisms that mediate the plasticity and aggressiveness of NCSC-like melanoma cells. Our preliminary studies identify a developmental LPAR1-YAP1 axis as critical for melanoma aggressiveness. One of the main objectives of this project will assess whether LPAR1-YAP1 activity represents an actionable vulnerability to ablate the metastatic potential and intrinsic resistance of NCSC-like cells. The proposed aims will leverage a multidisciplinary systems-biology approach spanning inducible genetic-editing techniques, lineage analysis of NCSC-like melanoma cells through time, metastatic patient-derived xenograft (Met-PDX) melanoma models, scRNAseq, RNA FISH and advanced bioinformatics, with the goal of translating the gained knowledge into novel therapeutic strategies for patients with advanced cancer. Another main goal is to establish an independent research program conducting multidisciplinary and collaborative research. To ensure the completion of the proposed work, my committee and I have identified four core competencies I will strengthen with continuous training, as well as didactic courses on single cell analysis and bioinformatic approaches. I will also participate in career training through workshops covering grant writing, manuscript preparation and presentation, responsible conduct of research, conflicts of interest, lab/budget management and guidance from my mentors. With the protected time and stability provided by the K01 award, as well as the comprehensive training I will receive, I am confident that I will be able to establish an independent research program and successfully acquire R01 funding. My short-term career goals are to: 1. Secure an independent faculty position and expand my scientific network of colleagues. 2. Define clonal diversity and molecular vulnerabilities of NCSC-like melanoma cells. 3. Continue to develop my scientific capabilities through my mentor/advisory committee and attain R01 funding. My long-term career goals are to: 1. Develop ongoing projects, expand into new directions and preclinical studies based on new results obtained. 2. Successfully renew R01 funding and attain alternate sources of funding, continue career development. 3. Translate discoveries clinically, train future mentees, and maintain a productive research program.